lecture 30 - the human microbiome Flashcards
How many species are found in the human microbiome?
10,000 species
What are commensal bacteria?
Bacteria that act on the host’s immune system to induce protective responses that prevent colonisation and invasion by pathogens. Found in the microbiome and prevent unwanted bacteria from colonising.
How do bacteria in the microbiome protect the body from pathogens?
Modifies environment to reduce virulence, make environment chemically hostile to invading pathogens, lower pH, signal host to produce more mucus, cause host to produce more antimicrobial peptides, e.g. defensins, promotes macrophage interactions.
What part of the body has the highest density of microbes?
The gastrointestinal/digestive tract
What does the gut microbiome produce that modulates metabolism and aids in immune system defence?
Produces SCFAs - short chain fatty acids.
How are SCFAs hostile ?
Short chain fatty acids are hostile to pathogens invading the gut.
What can the microbiome of the gut synthesise?
Vitamins
What vitamins can the microbiome of the gut synthesise?
B vitamins and vitamin K
What are probiotics?
Live microorganisms, commonly found in functional foods, that are meant to help build up the microbiome of the gut, particular after antibiotic use.
What are prebiotics?
An ingredient that nourishes bacteria in the gut microbiome - stimulate the growth of probiotics.
What are prebiotics generally derived from?
Oligosaccharides
What is the purpose of faecal microbiota transplantation?
Treatment of clostridium difficile infection, which occur after antibiotics as they are able to proliferate as pathogens.
What is the bacterial molecular ‘barcode’?
Each bacteria has a unique 16s rRNA sequence - with many available in databases to distinguish bacteria in samples.
What are 16s sequences?
Unique 16s rRNA (ribosomal RNA) sequences that can be used to distinguish between bacteria.
What are the aims of of the Human Microbiome Project?
To characterise and genomically sequence microbial communities found at multiple human body sites and identify correlations between changes in the microbiome and human health. Develop new technologies, explore legal and ethical implications
